The R&D Marine Flexible Coupling consists of a flexible disc molded with a Polyester Elastomer. The disc gives clearance for bolt heads, and is able to flex freely to take up any temporary misalignment of the engine and shaft, due to flexing of the boat structure or the engine moving on its mount. Forward thrust is taken in compression on the disc between the two half couplings and reverse thrust is taken again in compression on the disc between the two fail safe straps. In the unlikely event of a severe impact, the steel straps make the coupling fail safe and ensure drive is maintained both forward and reverse.
Reduce Engine Noise & Transmission Vibration
Staggered bolts enable the element to isolate vibrations and compensate for some misalignment.
Reduces Costly Transmission Repairs
Absorbs shock loads due to hard gear changes.
Fits Most Major Transmissions
For engines 5 to 1,500 horsepower. Fits brands such as Borg Warner, ZF-Hurth, Twin Disc, Volvo, Yanmar, Technodrive and more!
Under Compression Load In Both Forward & Reverse
The aft steel strap bolted to transmission acts as a backing plate to prevent reverse thrust from pulling the element apart.
Quick & Easy Installation
The R&D Marine Flexible Coupling requires no machining and comes supplied with bolts to connect between the two existing shaft flanges.
Impervious to salt water, diesel and lubrication oils. The Flexible Couplings are made from a polyester elastomer which is not affected by salt water, diesel or lubrication fluids.
Fail Safe Design
A fail safe design is incorporated in the R&D Flexible Shaft Coupling that prevents the two couplings from pulling apart in the event of an impact or element failure, whereas other couplings such as the Globe Rubber Drivesaver does not. This fail safe design is accomplished by using two steel straps and thru-bolts going into both the shaft coupling and transmission output flange. The aft steel strap is bolted to the transmission output flange and the front strap is bolted the shaft coupling. In the event of an impact the aft steel strap (bolted to the transmission) will catch the front steel strap (bolted to the shaft coupling) and prevent the drivetrain from pulling apart. The R&D element will absorb the shock load (reducing or eliminating damage to the transmission) and will maintain contact between the two couplings. The steel straps also keep the R&D Flex-Coupling under a compression load in both forward AND reverse operation (the aft strap bolted to the transmission acts as a backing plate).
Machined Not Molded
The Drivesaver is molded while the R&D Flexible Shaft Coupling is machined. Both designs suggested that you first set your alignment by drawing the two couplings up to each other and then add the flex-coupling. The machined part will have MUCH tighter tolerance than a molded part.
The R&D Flexible Shaft Coupling allows for inspection of alignment after the element is bolted in place. There is one bolt head that is machined and painted red. After the R&D Flexible Shaft Coupling is bolted into place, a feeler gauge can be slipped between the red bolt head and the coupling. This process is repeated with the same bolt four times at 90-degree intervals by rotating the shaft. If the gap is within .010” (0.25mm), the engine is accurately aligned.
We keep all the common R&D Marine Flexible Couplings in stock, however for a few of the less common sizes will have to be special ordered. Special Order Items will take approximately 2 to 3 weeks to ship out.